during all standard lifecycle phases of any JSF faces or
non-faces request.

The conversation context provides access to state associated
with a particular conversation. Every JSF request has an
associated conversation. This association is managed
automatically by the container according to the following
rules:

Any JSF request has exactly one associated conversation.

The conversation associated with a JSF request is determined
at the beginning of the restore view phase and does not change
during the request.

All long-running conversations have a string-valued unique
identifier, which may be set by the application when the
conversation is marked long-running, or generated by the container.

If the conversation associated with the current JSF request
is in the transient state at the end of a JSF request, it is
destroyed, and the conversation context is also destroyed.

If the conversation associated with the current JSF request
is in the long-running state at the end of a JSF request, it is
not destroyed. Instead, it may be propagated to other requests
according to the following rules:

The long-running conversation context associated with a
request that renders a JSF view is automatically propagated
to any faces request (JSF form submission) that originates
from that rendered page.

The long-running conversation context associated with a
request that results in a JSF redirect (a redirect resulting
from a navigation rule or JSF NavigationHandler) is
automatically propagated to the resulting non-faces request,
and to any other subsequent request to the same URL. This is
accomplished via use of a GET request parameter named cid
containing the unique identifier of the conversation.

The long-running conversation associated with a request
may be propagated to any non-faces request via use of a GET
request parameter named cid containing the unique identifier
of the conversation. In this case, the application must manage
this request parameter.

When no conversation is propagated to a JSF request, the
request is associated with a new transient conversation. All
long-running conversations are scoped to a particular HTTP
servlet session and may not cross session boundaries. In the
following cases, a propagated long-running conversation cannot
be restored and reassociated with the request:

When the HTTP servlet session is invalidated, all
long-running conversation contexts created during the current
session are destroyed, after the servlet service()
method completes.

The container is permitted to arbitrarily destroy any
long-running conversation that is associated with no current
JSF request, in order to conserve resources.